Glossary

Cabochons – dome shaped cut most commonly used in sapphires. Used to display asterism in star sapphires, cabochon cuts are applied to gems whose clarity is not ideal for faceting. Well-cut cabochons should display good symmetry with smooth un-cracked domes.

Carat – a unit used to measure the weight for precious stones. One carat equals 200 mg.

Corundum – an extremely hard mineral from which gem varieties such as ruby and sapphire fall under. Corundum contains aluminum oxide, iron, magnesia or silica.

Facet – a small, plane surface, often used to describe cuts in gems and precious stones.

Inclusions – any material trapped inside a stone. Inclusions range from other minerals or rocks, water and gases

Rutile – a red or black mineral commonly found as inclusions in sapphires.

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